Opengl Polygram Corners Issue

[k4pran]

Description of bug / unexpected behavior

In opengl the polygram example shows some corners are not rendered correctly when the width is increased. This may point to an issue in the shaders.

Expected behavior

Six even corners in the hexagon

How to reproduce the issue

Set the renderer to opengl

Code for reproducing the problem

class PolygramExample(Scene):
    def construct(self):
        hexagram = Polygram(
            [[0, 2, 0], [-np.sqrt(3), -1, 0], [np.sqrt(3), -1, 0]],
            [[-np.sqrt(3), 1, 0], [0, -2, 0], [np.sqrt(3), 1, 0]], stroke_width=20.
        )
        self.add(hexagram)

It only seems to cause an issue with two groups of vertices, rendering only one group results in a triangle with all corners connected correctly.

Additional media files

Images/GIFs

Cairo Render

Opengl Render

Opengl Render Wireframe (with blending disabled)

Logs

Terminal output

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System specifications

System Details

• OS (with version, e.g., Windows 10 v2004 or macOS 10.15 (Catalina)):
• RAM:
• Python version (python/py/python3 --version):
• Installed modules (provide output from pip list):

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LaTeX details

• LaTeX distribution (e.g. TeX Live 2020):
• Installed LaTeX packages:

FFMPEG

Output of ffmpeg -version:

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Additional comments

[MrDiver]

Yep because we do not have a polyline shader. So we are not able to choose between the different cap modes that are normally supported in cairo. Instead we just get seperate bezier curves forming a shape.